When Inari returns her powers to Uka, why doesn't she turn back to looking like Sumizome? Remember: Uka gave her those shapeshifting powers to enable her to return back to her original shape since wishes can not be reverted, so the wish to look like Sumizome would still be in effect.
It is shown that Uka can take the shape of a human being, as she did to help a young Touka when he got lost on shrine grounds. So why doesn't she do this after Inari returns her powers? She would still have been able to talk with Inari that way, even if only for a while.